A Kurdish peshmerga fighter prepares his weapon at his combat position near the Mosul Dam at the town of Chamibarakat outside Mosul, Iraq, Sunday, Aug 17, 2014. Kurdish forces took over parts of the largest dam in Iraq on Sunday less than two weeks after it was captured by the Islamic State extremist group, Kurdish security officials said, as U.S. and Iraqi planes aided their advance by bombing militant targets near the facility. (AP Photo/Khalid Mohammed)

A Kurdish peshmerga fighter prepares his weapon at his combat position near the Mosul Dam at the town of Chamibarakat outside Mosul, Iraq, Sunday, Aug 17, 2014. Kurdish forces took over parts of the largest dam in Iraq on Sunday less than two weeks after it was captured by the Islamic State extremist group, Kurdish security officials said, as U.S. and Iraqi planes aided their advance by bombing militant targets near the facility. (AP Photo/Khalid Mohammed)

A Kurdish peshmerga fighter patrols near the Mosul Dam at the town of Chamibarakat outside Mosul, Iraq, Sunday, Aug. 17, 2014. Kurdish forces took over parts of the largest dam in Iraq on Sunday less than two weeks after it was captured by the Islamic State extremist group, Kurdish security officials said, as U.S. and Iraqi planes aided their advance by bombing militant targets near the facility. (AP Photo/Khalid Mohammed)

Kurdish forces, known as peshmerga, stand guard near Mosul Dam at the town of Chamibarakat outside Mosul, Iraq, Sunday, Aug. 17, 2014. Kurdish forces took over parts of the largest dam in Iraq on Sunday less than two weeks after it was captured by the Islamic State extremist group, Kurdish security officials said, as U.S. and Iraqi planes aided their advance by bombing militant targets near the facility. (AP Photo/Khalid Mohammed)